diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -13,4 +13,8 @@
 - Change `Generator` to an open type family
 - Add `Generator` and `HasEndpoint` instances for `NoContentVerb`
 
+## 0.2.0.0
+- Fix Haddock build fail
+- Update aeson to 2.0.1.0
+
 ## Unreleased changes
diff --git a/servant-benchmark.cabal b/servant-benchmark.cabal
--- a/servant-benchmark.cabal
+++ b/servant-benchmark.cabal
@@ -1,84 +1,78 @@
-cabal-version: 1.12
-
--- This file has been generated from package.yaml by hpack version 0.34.4.
---
--- see: https://github.com/sol/hpack
---
--- hash: 861575a6df74fa9a62f3d04ddacc0e6bad1330403cfe2e203112f102af140569
+cabal-version:      1.12
+name:               servant-benchmark
+version:            0.2.0.0
+license:            BSD3
+license-file:       LICENSE
+copyright:          2021 Kyriakos Papachrysanthou
+maintainer:         papachrysanthou.k@gmail.com
+author:             Kyriakos Papachrysanthou
+homepage:           https://github.com/3kyro/servant-benchmark#readme
+bug-reports:        https://github.com/3kyro/servant-benchmark/issues
+synopsis:           Generate benchmark files from a Servant API
+description:
+    Please see the README on GitHub at <https://github.com/3kyro/servant-benchmark#README>
 
-name:           servant-benchmark
-version:        0.1.2.0
-synopsis:       Generate benchmark files from a Servant API
-description:    Please see the README on GitHub at <https://github.com/3kyro/servant-benchmark#README>
-category:       Web
-homepage:       https://github.com/3kyro/servant-benchmark#readme
-bug-reports:    https://github.com/3kyro/servant-benchmark/issues
-author:         Kyriakos Papachrysanthou
-maintainer:     papachrysanthou.k@gmail.com
-copyright:      2021 Kyriakos Papachrysanthou
-license:        BSD3
-license-file:   LICENSE
-build-type:     Simple
+category:           Web
+build-type:         Simple
 extra-source-files:
     README.md
     ChangeLog.md
 
 source-repository head
-  type: git
-  location: https://github.com/3kyro/servant-benchmark
+    type:     git
+    location: https://github.com/3kyro/servant-benchmark
 
 library
-  exposed-modules:
-      Servant.Benchmark
-      Servant.Benchmark.BasicAuth
-      Servant.Benchmark.Endpoint
-      Servant.Benchmark.Generator
-      Servant.Benchmark.HasEndpoint
-      Servant.Benchmark.HasGenerator
-      Servant.Benchmark.Tools.Drill
-      Servant.Benchmark.Tools.Siege
-      Servant.Benchmark.Tools.Wrk
-      Servant.Benchmark.ToText
-  other-modules:
-      Paths_servant_benchmark
-  hs-source-dirs:
-      src
-  ghc-options: -Wall
-  build-depends:
-      QuickCheck
-    , aeson
-    , base >=4.7 && <5
-    , base64-bytestring
-    , bytestring
-    , case-insensitive
-    , http-media
-    , http-types
-    , servant
-    , text
-    , yaml
-  default-language: Haskell2010
+    exposed-modules:
+        Servant.Benchmark
+        Servant.Benchmark.BasicAuth
+        Servant.Benchmark.Endpoint
+        Servant.Benchmark.Generator
+        Servant.Benchmark.HasEndpoint
+        Servant.Benchmark.HasGenerator
+        Servant.Benchmark.Tools.Drill
+        Servant.Benchmark.Tools.Siege
+        Servant.Benchmark.Tools.Wrk
+        Servant.Benchmark.ToText
 
+    hs-source-dirs:   src
+    other-modules:    Paths_servant_benchmark
+    default-language: Haskell2010
+    ghc-options:      -Wall
+    build-depends:
+        QuickCheck >=2.14.2 && <2.15,
+        aeson >=2.0.1.0 && <2.1,
+        base >=4.13 && <5,
+        base64-bytestring >=1.2.1.0 && <1.3,
+        bytestring >=0.10.12.1 && <0.11,
+        case-insensitive >=1.2.1.0 && <1.3,
+        http-media >=0.8.0.0 && <0.9,
+        http-types >=0.12.3 && <0.13,
+        servant >=0.18.3 && <0.19,
+        text >=1.2.4.1 && <1.3,
+        yaml >=0.11.7.0 && <0.12
+
 test-suite servant-benchmark-test
-  type: exitcode-stdio-1.0
-  main-is: Spec.hs
-  other-modules:
-      Paths_servant_benchmark
-  hs-source-dirs:
-      test
-  ghc-options: -threaded -rtsopts -with-rtsopts=-N -fprint-potential-instances
-  build-depends:
-      QuickCheck
-    , aeson
-    , base >=4.7 && <5
-    , base64-bytestring
-    , bytestring
-    , case-insensitive
-    , hspec
-    , http-media
-    , http-types
-    , servant
-    , servant-benchmark
-    , text
-    , utf8-string
-    , yaml
-  default-language: Haskell2010
+    type:             exitcode-stdio-1.0
+    main-is:          Spec.hs
+    hs-source-dirs:   test
+    other-modules:    Paths_servant_benchmark
+    default-language: Haskell2010
+    ghc-options:
+        -threaded -rtsopts -with-rtsopts=-N -fprint-potential-instances
+
+    build-depends:
+        QuickCheck >=2.14.2 && <2.15,
+        aeson >=2.0.1.0 && <2.1,
+        base >=4.13 && <5,
+        base64-bytestring >=1.2.1.0 && <1.3,
+        bytestring >=0.10.12.1 && <0.11,
+        case-insensitive >=1.2.1.0 && <1.3,
+        hspec >=2.8.3 && <2.9,
+        http-media >=0.8.0.0 && <0.9,
+        http-types >=0.12.3 && <0.13,
+        servant >=0.18.3 && <0.19,
+        servant-benchmark -any,
+        text >=1.2.4.1 && <1.3,
+        utf8-string >=1.0.2 && <1.1,
+        yaml >=0.11.7.0 && <0.12
diff --git a/src/Servant/Benchmark/Tools/Drill.hs b/src/Servant/Benchmark/Tools/Drill.hs
--- a/src/Servant/Benchmark/Tools/Drill.hs
+++ b/src/Servant/Benchmark/Tools/Drill.hs
@@ -7,6 +7,7 @@
 module Servant.Benchmark.Tools.Drill (Settings (..), export) where
 
 import Data.Aeson (ToJSON (..), object, (.=))
+import Data.Aeson.Key (fromText)
 import Data.Aeson.Types (Pair, Value)
 import qualified Data.ByteString as BS
 import Data.CaseInsensitive (original)
@@ -58,7 +59,7 @@
 
 headerToValue :: Header -> Pair
 headerToValue (headerName, value) =
-    toText (original headerName) .= toText value
+    fromText (toText (original headerName)) .= toText value
 
 -- | Export a benchmark file given a list of `Endpoint`s
 export :: FilePath -> Settings -> [Endpoint] -> IO ()
diff --git a/src/Servant/Benchmark/Tools/Wrk.hs b/src/Servant/Benchmark/Tools/Wrk.hs
--- a/src/Servant/Benchmark/Tools/Wrk.hs
+++ b/src/Servant/Benchmark/Tools/Wrk.hs
@@ -14,6 +14,7 @@
 module Servant.Benchmark.Tools.Wrk (export) where
 
 import Data.Aeson
+import Data.Aeson.Key (fromText)
 import Data.Aeson.Types (Pair)
 import qualified Data.ByteString as BS
 import qualified Data.ByteString.Lazy as BSL
@@ -47,7 +48,7 @@
 
 headerToValue :: Header -> Pair
 headerToValue (headerName, value) =
-    toText (original headerName) .= toText value
+    fromText (toText (original headerName)) .= toText value
 
 -- | Export a requests file given a list of `Endpoint`s
 export :: FilePath -> [Endpoint] -> IO ()
